The purpose of the Population Resources Core is to provide a central repository for all of the data characterizing populations included in the program project. Included in this core facility are: a) methods of recruitment of the populations; b) questionnaire instruments; c) methods of biosample collection; d) demographic descriptions of populations from which study populations were drawn; e) demographic data on individuals comprising study populations; f) pedigree structures; g) family history information; h) questionnaire-derived data; i) clinical information (patient records, pathology reports, etc.); j) tumor registry data; k) death registry, mortality information; l) description of the biosample collection (serum library, tissue bank); m) laboratory results from field study sites (Senegal, China, Alaska) and collaborating investigators (e.g. Santella, Sheffield) laboratory data from the General Laboratory Services Core. The information contained in the Population Resources Core is available to an investigators in the program project. Neither analyses of data nor laboratory studies are performed by the core; rather, the objectives of the core are to: 1) provide computer-based tools that facilitate the storage and retrieval of the data generated in the proposed research. Thus, the primary purpose of this core is to generate and maintain a working, "production" data base that provides access to common resources and information. 2) provide detailed descriptions of the available populations 3) insure the accuracy of the population data bases 4) organize and maintain the data bases to maximize their accessibility 5) correlate information among the projects By providing access to the data for all participants, as well as assuring the quality of the data, we believe that this core facility will not only facilitate achievement of the aims of the individual projects, but also encourage exploratory analyses beyond the stated aims of the projects.